1. Field of the Invention
The present disclosure relates to an apparatus and method for detecting steering information, and more particularly, to an apparatus and method in which a plurality of torque sensors and sensors for sensing a rotation angle of a steering shaft are provided to calculate steering information, such as a steering torque, a steering angle, etc., even upon occurrence of failure in some sensors.
2. Description of the Prior Art
In general, a power steering system is applied to a vehicle as a means for ensuring the stability of steering by reducing a force required to move a steering wheel. As a power steering system, a hydraulic power steering (HPS) system was widely used in vehicles in the past, but an electric power steering (EPS) system, which is environment-friendly and assists a driver in steering by using a turning force of a motor unlike the existing method employing hydraulic pressure, is usually installed in vehicles these days.
In such an EPS system, an electronic control unit (ECU) operates a motor according to driving conditions of a vehicle sensed by a speedometer, a torque sensor, and the like. Accordingly, the EPS system provides light and convenient feeling of steering during driving at low speed, provides heavy feeling of steering and sufficient directional stability during high-speed driving, and allows rapid steering in an emergency, thereby giving optimal conditions of steering to a driver.
An ECU of an existing EPS system measures a torque applied to a torsion bar and an absolute steering angle, which is the amount of rotation of a steering input shaft (IS), by using a first angle device for calculating an absolute steering angle and second and third angle devices for calculating a relative steering angle.
According to the existing method of sensing a torque and a steering angle, when failure occurs in the first, second, or third angle device, it is not possible to calculate either a torque value or a steering angle. Consequently, steering assistance is not controlled, and the stability of a vehicle may be considerably degraded.